I have moved the 4-inch line north of Richmond Metro area. I have also moved to 6-inch snow line out of the Lynchburg Roanoke areas because the data clearly shows there is going to be a weakness in the snow shield in the southern portions of the Virginia Piedmont. But the higher elevated terrain in Southwest Virginia will probably see 6 inch a lot of locations.
In looking at the LAST CALL map we are ONLY looking at short-range trends and the high-resolution short-range models. We are NOT looking like the European or the GFS model or the Canadian or anything like that.
In this discussion the focus is on the two primary short-range high-resolution models both of which have some pretty good skill scores. The first one is the high-resolution 3KM NAM model. In case you don’t know this is the primary short-range model which goes out to 60 hours which is used throughout the country. It has been continually upgraded as a pretty good model especially once you get within 36 hours.
First here is the new high-resolution 3km NAM snow forecast output. And its snow totals are stunningly huge but the way the model comes up with 12” of snow in northern Virginia DC BAL makes little sense. The model shows a large area of 12 inches of snow covering all of Southern New Jersey, Central and Northern Delmarva, just to the south of Baltimore, all of Southern Maryland, the DC and Northern Virginia Metro areas extending as far south as Fredericksburg, Charlottesville, and into Northern Shenandoah Valley.
Again we still have the issue of the really warm grounds and the rain so that has to be taken into consideration. But also when we take a look at the simulated radar from this model we see major problems.
Most of the data has been indicating that the rain is going to go to snow and sleet by around 3 a.m. in Washington DC and 4 a.m. in Charlottesville. However, this model still has its SLEETING in these areas at 7 a.m. Monday morning. In addition, there is a lot less snow on this map and a lot more rain when compared to the previous versions of this model. By 11 a.m. on Monday, we have heavy snow in Baltimore, southern New Jersey, the northern Delmarva, into most of northern Virginia, down into Charlottesville Roanoke and Lynchburg. Noticed that according to this model Richmond is STILL sleeting and it has not gone over to snow. That is a significant change for Central Virginia.
By 1 p.m. the 0z NAM model has the western edge of the snow line already approaching Washington DC and it has ended in Charlottesville, and it is about to end in Lynchburg. In other words the models shows a 5–6 where Washington DC and northern Virginia is going to pick up 12 inches of snow??/ With a wet and warm ground in 6 hours?
This makes no sense at all.
Absolutely none.
The next short Range model we take a look at is the HRRR or high-resolution rapidly updating model. This model is updated every hour and is useful to see Trends. It’s very good for depicting severe thunderstorms, high winds, and torrential rains, and heavy snow bands.
This image shows that at 4 a.m. on Monday this particular Model has it snowing in Washington DC several hours earlier than 0z 3KM NAM that I just talked about above. The sleet is about to change the snow in Charlottesville and it is raining and sleeting in Roanoke and snowing heavily in southwest Virginia, eastern Kentucky and the eastern third of West Virginia.
By 7 a.m. the sleet line is moved into Richmond Metro area ( about as expected) and it has changed over to snow in Lynchburg, Farmville, and Fredericksburg. Meanwhile, Roanoke Blacksburg and southwest Virginia, most of the Shenandoah Valley, Charlottesville, the northern Virginia Piedmont, the Washington D.C Baltimore Metro areas, northern Delaware are all getting pounded with heavy snow.
By 10 a.m. on Monday morning It is still snowing like hell in the same areas but it is still sleeting and snowing mix in Richmond. Noticed that in Winston-Salem and Greensboro, the wrap around precipitation and north winds have pushed the rain over to all snow. Also moderate snow has pushed into the Philadelphia metro area. I have drawn in a thick black line to show the western edge of the snow Shield.
By 1 PM the heavy snow band has shifted considerably to the east which we can see with the thick black line showing the western edge of the snow shield. It has at this point ended in all of Western North Carolina, southwest Virginia, most of the Shenandoah Valley, and will be ending in the Virginia Piedmont, Washington DC, and Baltimore Philadelphia and northern Delaware by 2 or 3 p.m. . In Central Virginia it is snowing like hell in the Richmond Metro area which extends down into Raleigh and Greensboro as well as Roanoke Rapids, Danville, South Hill, and South Boston areas.
Notice at this point in time Southeast Virginia Hampton Roads has dry slotted completely with nothing falling out of the sky whatsoever.
Finally by 4 p.m. the snow continues to fall heavily in the Delmarva throughout the day and into Hampton Roads and Northeast North Carolina. It looks like it is about to end in the Richmond Metro area. At this point, temperatures have crashed and are already in the middle 20s in central and eastern Virginia and it is at this point in time where Central Virginia and Richmond will see the snow pile up — 11A-4PM
The HRRR Adjusted snow map makes a lot of sense and it supports my idea for the LAST CALL MAP
And finally this is really important. The slush and snow on the roads especially secondary roads and bridges and overpasses will freeze hard Monday night. Temperatures are going to crash big time
By 7 p.m. all of Virginia except for the coastal areas of Hampton Roads and the Bay regions will have temperatures between 22 and 26 degrees. The Shenandoah Valley into the eastern portions of West Virginia and interior Southwest Virginia will have temperatures around 20–22 degrees. By midnight most areas in Virginia will have temperatures ranging between 18–24 degrees and that is also the case in most of Maryland and the Delmarva with low teens possible in eastern portions of West Virginia and Southwest Virginia by midnight going into early Tuesday morning.
Now it’s time for some sleep and we are moving into short-term now casting